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CM 1A: Heme/Onc/Endo > Lecture 21: Male Gonadal Disorders > Flashcards

Lecture 21: Male Gonadal Disorders Flashcards

1
Q

Describe the Hypothalamus-Pituitary-Gonadal Axis in males. (HPG)

A
  1. Hypothalamus secretes GnRH to stimulate anterior pituitary every 2 hours (pulsatile)
  2. Anterior pituitary releases FSH and LH
  3. FSH stimulates Sertoli cells in testes to regulate spermatogenesis and produce inhibin B
  4. Inhibin B provides negative feedback to stop FSH.
  5. LH stimulates Leydig cells to produce testosterone.
  6. Testosterone provides negative feedback to stop LH, but assists FSH in spermatogenesis.

FSH = for sperm hormone

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2
Q

What does LH allow the uptake of in Leydig cells?

A

Cholesterol, which is converted to testosterone.

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3
Q

What is testosterone converted to? Where?

A

It is converted to either DHT or estradiol.

Majority of the conversion occurs in the peripheral tissues.

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4
Q

What are the additional functions of testosterone?

A
  • Sexual health
  • Mood (increased aggression, decreased depression)
  • Improve cognition/memory
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5
Q

Where is the majority of testosterone produced?

A

Testicles.

5% in adrenal glands.

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6
Q

What is 98% of testosterone bound to?

A

60%: Sex hormone-binding globulin (SHBG)
38%: Albumin

SHBG has a higher binding affinity.

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7
Q

What is the remaining 2% of unbound testosterone for?

A

Physiologically active.

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8
Q

What is unique about albumin-bound testosterone?

A

It can dissociate readily in capillaries.

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9
Q

Where is testosterone metabolized/excreted?

A

Metabolized in the liver.
Excreted via the kidneys.

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10
Q

What two processes begin to ramp up to initiate puberty?

A
  • Adrenarche in the zona reticularis to produce androgens (6-8y)
  • Gonadarche (Activation of HPG axis, around 9y)
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11
Q

How do we stage male puberty development?

A

Tanner stages, beginning at 1 and ending at 5.

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12
Q

What are the first signs of male puberty?

A
  • Growth of testes
  • Pubic/axillary hair growth
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13
Q

How do we measure testicle size clinically? What qualifies as adult size?

A

Prader orchidometer, with 12-25 mL being adult size.

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14
Q

If we do not have a prader orchidometer at hand, what else can suggest that a male has entered puberty?

A

Testicular size > 2.5cm longitudinally.

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15
Q

What qualifies as precocious puberty?

A

Evidence of puberty in boys prior to the age of 9.

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16
Q

What are the two types of precocious puberty?

A
  • Isosexual: premature development of phenotypically appropriate secondary sexual characteristics.
  • Heterosexual: Development of secondary sexual characteristics of the opposite sex.
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17
Q

What are the two subtypes of isosexual precocity?

A
  • Gonadotropin-dependent (Central precocious puberty)
  • Gonadotropin-independent (Peripheral precocious puberty)
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18
Q

What is the pathophysiology behind central precocious puberty? (CPP)

A

CPP is caused by a PREmature activation fo the GnRH pulse generator, causing inappropriately elevated GnRH levels.

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19
Q

What is the pathophysiology behind peripheral precocious puberty?

A

Androgens from the testes or adrenal glands are increased, but gonadotropin levels are low.

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20
Q

What is the MC of CPP?

A

Idiopathic

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21
Q

What is the MC of peripheral precocious puberty?

A

CAH

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22
Q

What is the 2nd likely etiology for CPP and what might suggest it?

A

CNS lesions.

  • History red flags: HA, seizures, N/V, memory/vision changes, loss of balance, etc.
  • PE red flag: abnormal neuro exam
  • Imaging: Abnormal MRI brain w/ contrast
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23
Q

What two tumors can cause peripheral precocious puberty?

A
  • hCG tumor
  • Androgen secreting tumor in the zona reticularis
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24
Q

What two enzyme deficiencies in CAH typically lead to precocious puberty?

A
  • 21-hydroxylase
  • 11-hydroxylase
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25
Q

What syndrome more common in females can lead to peripheral precocious puberty in males? How?

A

McCune-Albright syndrome (MAS)

A mutation in the activation of adenylyl cyclase results in testosterone production.

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26
Q

What triad of findings suggests McCune Albright?

A
  1. Bone dysplasia
  2. Cafe-au-lait skin pigmentation
  3. Precocious puberty
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27
Q

What autosomal dominant disorder can lead to peripheral precocious puberty?

A

Familial male-limited precocious puberty, which results in LH activation errors, causing testosterone synthesis.

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28
Q

What simple and exogenous way can males enter precocious puberty?

A

Exogenous androgen exposure like testosterone cream.

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29
Q

What historical findings are important to know for suspected puberty issues?

A
  • Onset
  • Progression
  • Assess CNS disease
  • Exposures
  • Family history of puberty onsets/conditions
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30
Q

If a patient presents with enlarged testes, what are the more likely etiologies?

A
  • CPP
  • hCG tumor (mild)
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31
Q

If a patient presents with small testes but precocious puberty, what are the more likely etiologies?

A
  • Adrenal etiologies
  • Familial male precocious puberty
  • Exogenous androgens
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32
Q

What finding could suggest testicular tumor?

A

Asymmetry or unilateral testicular enlargement

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33
Q

What imaging should be ordered for suspected precocious puberty?

A

Left wrist and hand XRAY to assess bone age.

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34
Q

What is being assessed in an XRAY of the left hand and wrist?

A
  • Linear growth
  • Skeletal maturation/bone age
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35
Q

What are the two lab tests we should order for initial evaluation of suspected precocious puberty? Expected results?

A
  • Serum testosterone: elevated in all types.
  • Serum LH/FSH: only elevated in CPP.
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36
Q

What secondary lab tests would be elevated in precocious puberty? What etiologies are they linked to?

A
  • Serum hCG elevated in hCG tumor
  • DHEA elevated in CAH or adrenal tumor
  • 17a-hydroxyprogesterone elevated in CAH
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37
Q

What test can we run to differentiate CPP from peripheral? What result indicates CPP?

A

GnRH analogue (Leuprolide) stimulation test.

Rise in LH when administered indicates CPP.

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38
Q

What genetic testing would we run for precocious puberty?

A

LH/GS-alpha subunit mutation test if we suspect McCune Albright.

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39
Q

After we get our XRAY, what other imaging modalities might we use for evaluating precocious puberty? What do they rule out?

A
  • MRI brain: r/o CNS lesion with CPP or if theres elevated hCG.
  • CT Chest/Abd: r/o hCG tumor or adrenal tumors.
  • Testicular US: r/o Leydig-cell tumors
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40
Q

How do we treat CPP?

A
  • Treat underlying cause (if tumor)
  • Idiopathic requires long-acting GnRH agonists.
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41
Q

Describe the MOA of a long-acting GnRH agonist.

A

Initially, LH/FSH secretion will increase.

However, long-term use will result in densensitization of the receptors, reducing them to prepubertal levels. (Takes about 2 weeks to do so)

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42
Q

What are the effects of long-acting GnRH agonists?

A
  • Halts early pubertal development
  • Delay bone maturation
  • Prevent early epiphyseal closure, increasing final height.
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43
Q

How is leuprolide administered?

A

Depot injections every 1, 3, or 6 months

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44
Q

What is the alternative to leuprolide?

A

Histrelin SQ implant annually.

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45
Q

How do we treat peripheral precocious puberty?

A
  • Tumor excision
  • Removal of exogenous steroids
  • Glucocorticoids to suppress CAH
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46
Q

How do we treat McCune Albright syndrome and Familial male-limited precocious puberty?

A

Combination of androgen receptor antagonists (spironolactone) with aromatase inhibitors (anastrozole) to prevent the conversion of testosterone to estradiol.

Alternative: steroid synthesis inhibitor (ketoconazole)

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47
Q

What is the risk with using ketoconazole to treat something like MAS?

A

You may require high dosages, which can induce hepatoxicity.

48
Q

What qualifies as delayed male puberty?

A

Lack of testicular enlargement by age 14 OR incomplete genital growth within 5 years of puberty onset.

49
Q

What are the two categories of delayed male puberty?

A
  • Primary hypogonadism
  • Secondary hypogonadism
50
Q

What is the primary cause of delayed puberty?

A

Secondary hypogonadism secondary to constitutional delay of growth and puberty (CDGP)

51
Q

What are the 6 MCC of delayed puberty?

A
  1. CDGP
  2. Systemic disorders
  3. CNS tumors and treatment
  4. Hypothalamic-pituitary causes (Low gonadotropins)
  5. Gonadal causes (High gonadotropins)
  6. Androgen insensitivity
52
Q

What congenital abnormalities suggest Kallman syndrome?

A
  • Altered sense of smell
  • Synkinesia
53
Q

What does a family history of delayed/absent puberty suggest?

A

CDGP

54
Q

What are the congenital abnormalities that may suggest delayed puberty?

A
  • Altered sense of smell
  • Microphallus
  • Cryptorchidism (increased risk of testicular cancer)
  • Synkinesia
  • Renal agenesis
55
Q

What wingspan difference suggests a delayed epiphyseal closure secondary to hypogonadism?

A

Wingspan exceeding height by 5 cm

56
Q

What testicle size might suggest delayed puberty?

A
  • 1-3 mL using a prader orchidometer.
  • < 2.5cm longitudinally
57
Q

What would our initial assessment for delayed puberty involve?

A
  • XRAY L hand/wrist
  • Serum testosterone (low)
  • Gonadotropin levels
58
Q

What XRAY findings suggest CDGP?

A
  • Bone age delayed relative to actual age.
  • Normal growth velocity.
59
Q

If a patient presents with delayed puberty and has an elevated FSH/LH, what etiology does that suggest? Decreased?

A
  • Elevated: Primary hypogonadism or gonadal failure.
  • Decreased: Secondary hypogonadism.
60
Q

If a patient has suspected CDGP, what is the treatment?

A
  • Reassurance with f/u
  • Testosterone therapy (if patient’s self-esteem is affected)
61
Q

How do I treat primary and secondary hypogonadism?

A
  • Primary: Indefinite testosterone replacement.
  • Secondary: Testosterone replacement for 6mo, then interrupt to check endogenous secretion of FSH/LH.
62
Q

Adding what medication can help increase adult height for those with delayed puberty?

A

Aromatase inhibitor like anastrozole.

63
Q

What is hypogonadism?

A

Failure of the testes to produce adequate testosterone

64
Q

What are the 3 classifications of hypogonadism?

A
  • Hypergonadotrophic: pathology of the testes resulting in low testosterone but high LH.
  • Hypogonadotrophic: insufficient secretion from hypothalamus/pituitary, resulting in low testosterone and low LH.
  • Both
65
Q

If hypogonadism presents early on in the fetus, such as by the 2nd month, what might occur to the fetus’ gonads?

A
  • Ambiguous genitalia
  • Male pseudohermaphroditism
66
Q

If hypogonadism occurs in a fetus late in gestation, such as the 3rd trimester, what might it affect?

A
  • Cryptorchidism
  • Micropenis
67
Q

How does an adult that went through delayed puberty untreated often present?

A
  • Decreased energy/libido
  • Decreased morning wood
  • Loss of pubic/axillary
  • Decreased muscle mass
  • Increased fat mass with bone mineral density decreases
  • Possible infertility
68
Q

What are the 3 goals of a clinical evaluation for hypogonadism?

A
  1. Determine if S/S occurred prior to or post puberty.
  2. Determine if patient has normal genitalia.
  3. Determine if hypogonadism is primary or secondary.
69
Q

What is the first step in evaluating hypogonadism?

A

Morning total testosterone

70
Q

If a patient presents with low morning testosterone levels, what is the next step?

A
  • Draw it 2x more.
  • Draw LH and FSH levels.
71
Q

If a patient presents with low total testosterone and normal/low LH/FSH, what is the suspected etiology?

A

Secondary hypogonadism

72
Q

If a patient presents with low total testosterone but elevated FSH/LH, what is the suspected etiology?

A

Primary hypogonadism

73
Q

What are the indications for testosterone replacement therapy?

A
  • Lack of puberty by age 14 (delayed puberty)
  • Primary testicular failure/hypergonadotrophic hypogonadism
  • Severe hypogonadotrophic hypogonadism (Secondary) with total testerone < 150 ng/mL
  • Age-related hypogonadism
74
Q

What is andropause?

A

Decrease in testosterone production usually between 40-60, greatest in obese and chronically ill men.

Everything in the HPG axis becomes slowly impaired.

75
Q

When should you test for low testosterone levels?

A

Only when symptoms are present

76
Q

For age-related hypogonadism, when is testosterone replacement therapy indicated?

A
  • 3+ androgen deficiency symptoms
  • Testosterone < 200 ng/dL
  • Benefits outweigh risk
77
Q

What are the androgen deficiency symptoms?

A
  • ED
  • Poor Morning wood
  • Low libido
  • Depression
  • Fatigue
  • Inability to perform vigorous activity
78
Q

When is testosterone generally the highest?

A

8-10AM

79
Q

If a fasting morning testosterone is low, what should we do?

A

Repeat it

80
Q

If we have a persistently low morning testosterone, what test can we order to further evaluate it?

A

Free testosterone

Should be linear. If not, possible abnormal function or abnormal SHBG.

81
Q

What hormones does SHBG bind to?

A
  • Testosterone
  • DHT
  • Estradiol
82
Q

When do we order a SHBG test?

A
  • Suspected abnormality in testosterone binding to SHBG coexists with hypogonadism.
  • No free testosterone assay available.
83
Q

What is the primary cause of elevated SHBG?

A

Age

84
Q

What is the primary cause of decreased SHBG?

A

Obesity

85
Q

What does high LH suggest? High FSH?

A
  • Elevated LH: Primary hypogonadism
  • Elevated FSH: Damage to seminiferous tubules

Normal/low of both with low T indicates secondary hypogonadism

86
Q

When is an Inhibin B test ordered? What interpretation are we looking for?

A

Suspicion of damage to Sertoli cells.

Decreased would mean damage to the seminiferous tubules.

87
Q

When is a semen analysis indicated?

A

Infertility

88
Q

What does a normal semen analysis often exclude at the same time?

A

Gonadal dysfunction.

89
Q

What is the criteria for an abnormal semen analysis?

A

At least 3 semen samples studied for 2-3 months since sperm takes 3 months to mature.

90
Q

How quickly must semen analysis be performed?

A

Within 1 hour of collection.

91
Q

What are the two indications for a testicular biopsy?

A
  1. Hypogonadal men with normal-sized testes and azoospermia to distinguish between spermatogenic failure vs ductal obstruction.
  2. Harvesting of sperm for ICSI.
92
Q

What is gynecomastia?

A

Enlargement fo the male breast dt excess estrogen.

Glandular breast tissue > 4cm in diameter and is tender upon palpation.

93
Q

What is the cause of pathologic gynecomastia?

A

Increased aromatase activity.

94
Q

For gynecomastia, when is pain/tenderness of the breast MC age-wise?

A

Usually only painful/tender in adolescents.

95
Q

Describe breast tissue that is normal vs malignant.

A

Normal: subareolar, symmetrical, bilateral, tender (early on)
Malignant: Unilateral, non-tender, offset from areola.

96
Q

What are the 3 red flags on a clinical breast exam that warrant further investigation?

A
  • New onset or rapid unilateral growth.
  • Non-tender mass
  • Fixed mass lateral to areola.
97
Q

What are the 4 primary causes of gynecomastia? Treatment?

A

Pubertal: reassurance, self-resolving in 1-2yrs.
Drug-induced: stop taking drug and monitor.
Androgen deficiency: Testosterone replacement
hCG tumor: MRI/CT and refer to surgery

98
Q

If high levels of estradiol are present with normal testosterone, what is the suspect etiology and treatment?

A

Assess for Sertoli and adrenal tumors.
Refer to surgery once MRI/CT obtained.

99
Q

If a patient with gynecomastia shows no improvement after 9-12 months, what is the treatment? What if its been 12+ months?

A
  • Selective estrogen receptor modulator (tamoxifen)
  • Aromatase inhibitor (anastrozole)

12+ months = surgery

100
Q

What drug schedule is testosterone replacement?

A

Schedule III

101
Q

What can testosterone not restore?

A

Fertility.

102
Q

What are the 2 week versions of testosterone injections called?

A
  • Testosterone enanthate
  • Testosterone cypionate
103
Q

What is the long-acting testosterone injection called? What counseling/precautions are required?

A

Testosterone undecanoate.

  • 1 dose and then 2nd dose in 4 weeks.
  • 10 weeks per dose afterwards.
  • All doses must be given IN OFFICE with provider monitoring for 30 mins and completing REMS.
104
Q

What other routes can testosterone be administered?

A
  • Gel
  • Solution
  • Pellets (into your butt, lower abd wall, or thighs)
  • Nasal gel
  • Oral (decanoate)
105
Q

What are the goals of testosterone replacement therapy?

A
  • Restore levels to normalish
  • Promote development and maintenance of secondary sexual characteristics and normal sexual function.
  • Build/sustain normal bone/muscle mass
  • Psychosocial adjustment for teens
106
Q

How often do we measure people being given testosterone injections?

A

Midway between injections.

107
Q

How often do we measure patients being given testosterone gel/solution?

A

Anytime after 1 week of therapy.

108
Q

How often do we measure patients being given nasal gel testosterone?

A

After 1 month of therapy.

109
Q

What CBC measurement would indicate us to stop testosterone therapy?

A

Hematocrit > 54%
Evaluate for hypoxia and sleep apnea.

110
Q

After 1 year of testosterone therapy in hypogonadal males, what bones do we measure and why?

A

Bone mineral density in lumbar and femur.
Osteoporosis

111
Q

If a patient is over 40 and has an elevated PSA, what do we need to check and when?

A
  • DRE and PSA check prior to starting testosterone.
  • 3-6 months 2nd check.
112
Q

What 3 findings would indicate a need for urologic consultation for a patient on testosterone therapy?

A
  1. Increase in serum PSA > 1.4 within a 12 month period.
  2. PSA velocity > 0.4 annually after at least 6 months of testosterone therapy.
  3. Prostatic abnormality on DRE.
113
Q

What formulation specific adverse effects should we ask patients on testosterone therapy EVERY VISIT?

A
  • Injection: Mood fluctuations or cough post injection.
  • Gels: Wash site after application to make sure it doesn’t get onto others.
  • Nasal gel: nasal irritation or epistaxis.
114
Q

What two conditions are associated with extremely high risk of adverse effects if given testosterone?

A
  • Metastatic prostate cancer
  • Breast cancer
115
Q

What are the 4 guidelines by the endocrine society regarding testosterone replacement therapy?

A
  1. Avoid in patients with mild vague symptoms or only a one-time low reading.
  2. Avoid trial therapy.
  3. Therapy suppresses pituitary-testicular axis.
  4. Therapy suppresses spermatogenesis and decreases testicular size.

CM 1A: Heme/Onc/Endo (28 decks)

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